Le 04/03/2021 à 12:31, Marco Elver a écrit :
On Thu, 4 Mar 2021 at 12:23, Christophe Leroy
<christophe.le...@csgroup.eu> wrote:
Le 03/03/2021 à 11:56, Marco Elver a écrit :
Somewhat tangentially, I also note that e.g. show_regs(regs) (which
was printed along the KFENCE report above) didn't include the top
frame in the "Call Trace", so this assumption is definitely not
isolated to KFENCE.
Now, I have tested PPC64 (with the patch I sent yesterday to modify
save_stack_trace_regs()
applied), and I get many failures. Any idea ?
[ 17.653751][ T58]
==================================================================
[ 17.654379][ T58] BUG: KFENCE: invalid free in
.kfence_guarded_free+0x2e4/0x530
[ 17.654379][ T58]
[ 17.654831][ T58] Invalid free of 0xc00000003c9c0000 (in kfence-#77):
[ 17.655358][ T58] .kfence_guarded_free+0x2e4/0x530
[ 17.655775][ T58] .__slab_free+0x320/0x5a0
[ 17.656039][ T58] .test_double_free+0xe0/0x198
[ 17.656308][ T58] .kunit_try_run_case+0x80/0x110
[ 17.656523][ T58] .kunit_generic_run_threadfn_adapter+0x38/0x50
[ 17.657161][ T58] .kthread+0x18c/0x1a0
[ 17.659148][ T58] .ret_from_kernel_thread+0x58/0x70
[ 17.659869][ T58]
[ 17.663954][ T58] kfence-#77 [0xc00000003c9c0000-0xc00000003c9c001f,
size=32, cache=kmalloc-32]
allocated by task 58:
[ 17.666113][ T58] .__kfence_alloc+0x1bc/0x510
[ 17.667069][ T58] .__kmalloc+0x280/0x4f0
[ 17.667452][ T58] .test_alloc+0x19c/0x430
[ 17.667732][ T58] .test_double_free+0x88/0x198
[ 17.667971][ T58] .kunit_try_run_case+0x80/0x110
[ 17.668283][ T58] .kunit_generic_run_threadfn_adapter+0x38/0x50
[ 17.668553][ T58] .kthread+0x18c/0x1a0
[ 17.669315][ T58] .ret_from_kernel_thread+0x58/0x70
[ 17.669711][ T58]
[ 17.669711][ T58] freed by task 58:
[ 17.670116][ T58] .kfence_guarded_free+0x3d0/0x530
[ 17.670421][ T58] .__slab_free+0x320/0x5a0
[ 17.670603][ T58] .test_double_free+0xb4/0x198
[ 17.670827][ T58] .kunit_try_run_case+0x80/0x110
[ 17.671073][ T58] .kunit_generic_run_threadfn_adapter+0x38/0x50
[ 17.671410][ T58] .kthread+0x18c/0x1a0
[ 17.671618][ T58] .ret_from_kernel_thread+0x58/0x70
[ 17.671972][ T58]
[ 17.672638][ T58] CPU: 0 PID: 58 Comm: kunit_try_catch Tainted: G B
5.12.0-rc1-01540-g0783285cc1b8-dirty #4685
[ 17.673768][ T58]
==================================================================
[ 17.677031][ T58] # test_double_free: EXPECTATION FAILED at
mm/kfence/kfence_test.c:380
[ 17.677031][ T58] Expected report_matches(&expect) to be true, but is
false
[ 17.684397][ T1] not ok 7 - test_double_free
[ 17.686463][ T59] # test_double_free-memcache: setup_test_cache:
size=32, ctor=0x0
[ 17.688403][ T59] # test_double_free-memcache: test_alloc: size=32,
gfp=cc0, policy=any,
cache=1
Looks like something is prepending '.' to function names. We expect
the function name to appear as-is, e.g. "kfence_guarded_free",
"test_double_free", etc.
Is there something special on ppc64, where the '.' is some convention?
I think so, see
https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUNC-DES
Also see commit https://github.com/linuxppc/linux/commit/02424d896
Christophe
